BSD 4_3_Net_2 release

[unix-history] / usr / src / lib / libc / stdio / ungetc.3

diff --git a/usr/src/lib/libc/stdio/ungetc.3 b/usr/src/lib/libc/stdio/ungetc.3
index 690ecc9..149ddfd 100644 (file)
--- a/usr/src/lib/libc/stdio/ungetc.3
+++ b/usr/src/lib/libc/stdio/ungetc.3
@@ -1,55 +1,95 @@
-.\" Copyright (c) 1990 The Regents of the University of California.
+.\" Copyright (c) 1990, 1991 The Regents of the University of California.

 .\" All rights reserved.
 .\"
 .\" This code is derived from software contributed to Berkeley by
 .\" All rights reserved.
 .\"
 .\" This code is derived from software contributed to Berkeley by

-.\" Chris Torek.
+.\" Chris Torek and the American National Standards Committee X3,
+.\" on Information Processing Systems.

 .\"
 .\"

-.\" %sccs.include.redist.man%
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\" 3. All advertising materials mentioning features or use of this software
+.\"    must display the following acknowledgement:
+.\"    This product includes software developed by the University of
+.\"    California, Berkeley and its contributors.
+.\" 4. Neither the name of the University nor the names of its contributors
+.\"    may be used to endorse or promote products derived from this software
+.\"    without specific prior written permission.

 .\"
 .\"

-.\"    @(#)ungetc.3    6.3 (Berkeley) %G%
+.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+.\" SUCH DAMAGE.

 .\"
 .\"

-.TH UNGETC 3 ""
-.UC 7
-.SH NAME
-ungetc \- push character back into input stream
-.SH SYNOPSIS
-.nf
-.ft B
-#include <stdio.h>
-
-int
-ungetc(int c, FILE *stream);
-.fr R
-.fi
-.SH DESCRIPTION
-.I Ungetc
-pushes the integer
-.I c
-(converted to an ``unsigned char'') back on an input stream, so that
-the next
-.I getc
-call on that stream will return
-.IR c .
-.I Ungetc 
-returns 
-.IR c .
-.PP
-One character of pushback is always guaranteed, but as long as there is
+.\"     @(#)ungetc.3   6.6 (Berkeley) 6/29/91
+.\"
+.Dd June 29, 1991
+.Dt UNGETC 3
+.Os
+.Sh NAME
+.Nm ungetc
+.Nd un-get character from input stream
+.Sh SYNOPSIS
+.Fd #include <stdio.h>
+.Ft int
+.Fn ungetc "int c" "FILE *stream"
+.Sh DESCRIPTION
+The
+.Fn ungetc
+function pushes the character
+.Fa c
+(converted to an unsigned char)
+back onto the input stream pointed to by
+.Fa stream .
+The pushed-backed characters will be returned by subsequent reads on the
+stream (in reverse order).
+A successful intervening call, using the same stream, to one of the file
+positioning functions
+.Po
+.Xr fseek 3 ,
+.Xr fsetpos 3 ,
+or
+.Xr rewind 3
+.Pc
+will discard the pushed back characters.
+.Pp
+One character of push-back is guaranteed,
+but as long as there is

 sufficient memory, an effectively infinite amount of pushback is allowed.
 sufficient memory, an effectively infinite amount of pushback is allowed.

-Attempts to push
-.B EOF
-are rejected.
-.PP
-A successful call to
-.I fseek
-erases all memory of pushed back characters.
-.SH "SEE ALSO"
-getc(3), fseek(3), setvbuf(3)
-.SH "RETURN VALUE"
-.I Ungetc
+.Pp
+If a character is successfully pushed-back,
+the end-of-file indicator for the stream is cleared.
+.Sh RETURN VALUES
+The
+.Fn ungetc
+function

 returns
 returns

-.SM
-.B EOF
-if it cannot push back the given character for any reason
-(this includes attempts to push
-.BR EOF ).
+the character pushed-back after the conversion, or
+.Dv EOF
+if the operation fails.
+If the value of the argument
+.Fa c
+character equals
+.Dv EOF ,
+the operation will fail and the stream will remain unchanged.
+.Sh SEE ALSO
+.Xr getc 3 ,
+.Xr fseek 3 ,
+.Xr setvbuf 3
+.Sh STANDARDS
+The
+.Fn ungetc
+function conforms to
+.St -ansiC .